The prevention of localized ridge deformities using guided tissue regeneration
An extraction of a tooth which causes the loss of the buccal alveolar plate of bone may heal with a localized ridge deformity. This is due to the elimination of the four-walled socket in which the blood clot forms and is protected. Extraskeletal connective tissue then grows into the space originally occupied by the tooth, and a combination of bone and soft tissue fill the socket defect. One of the reasons for localized ridge defects is the loss of bone prior to the removal of the tooth. The reasons may include developmental defects, periodontal disease, vertical tooth fracture, abscess formation, surgical trauma, or traumatic injury. These defects cause problems when osseointegrated implants are to be placed. The best solution is to prevent the occurrence of the defects. This would require filling the extraction socket with new bone, which would provide a firm vascular base upon which secondary soft-tissue grafts and/or implant fixtures could be placed if required. This can be achieved by using an expanded polytetrafluoroethylene (ePTFE) membrane following extraction. The membrane maintains the space for the initial clot, protecting it during organization, and prevents extraskeletal connective tissue from invading the extraction socket. The same principles can be applied to previous extraction sockets that already have localized ridge deformities. It is a technique that is divided into two surgical phases. Phase I involves tooth/root extraction and membrane placement. Phase II consists of membrane removal. [M.J.D.]
O'Brien,T.P., J.E. Hinrichs, and E.M. Schaffer, J Periodont, 65:17, 1994